| /* |
| * linux/fs/open.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| #include <linux/string.h> |
| #include <linux/mm.h> |
| #include <linux/file.h> |
| #include <linux/fdtable.h> |
| #include <linux/fsnotify.h> |
| #include <linux/module.h> |
| #include <linux/tty.h> |
| #include <linux/namei.h> |
| #include <linux/backing-dev.h> |
| #include <linux/capability.h> |
| #include <linux/securebits.h> |
| #include <linux/security.h> |
| #include <linux/mount.h> |
| #include <linux/fcntl.h> |
| #include <linux/slab.h> |
| #include <asm/uaccess.h> |
| #include <linux/fs.h> |
| #include <linux/personality.h> |
| #include <linux/pagemap.h> |
| #include <linux/syscalls.h> |
| #include <linux/rcupdate.h> |
| #include <linux/audit.h> |
| #include <linux/falloc.h> |
| #include <linux/fs_struct.h> |
| #include <linux/ima.h> |
| #include <linux/dnotify.h> |
| #include <linux/compat.h> |
| |
| #include "internal.h" |
| |
| int do_truncate2(struct vfsmount *mnt, struct dentry *dentry, loff_t length, |
| unsigned int time_attrs, struct file *filp) |
| { |
| int ret; |
| struct iattr newattrs; |
| |
| /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */ |
| if (length < 0) |
| return -EINVAL; |
| |
| newattrs.ia_size = length; |
| newattrs.ia_valid = ATTR_SIZE | time_attrs; |
| if (filp) { |
| newattrs.ia_file = filp; |
| newattrs.ia_valid |= ATTR_FILE; |
| } |
| |
| /* Remove suid, sgid, and file capabilities on truncate too */ |
| ret = dentry_needs_remove_privs(dentry); |
| if (ret < 0) |
| return ret; |
| if (ret) |
| newattrs.ia_valid |= ret | ATTR_FORCE; |
| |
| mutex_lock(&dentry->d_inode->i_mutex); |
| /* Note any delegations or leases have already been broken: */ |
| ret = notify_change2(mnt, dentry, &newattrs, NULL); |
| mutex_unlock(&dentry->d_inode->i_mutex); |
| return ret; |
| } |
| int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, |
| struct file *filp) |
| { |
| return do_truncate2(NULL, dentry, length, time_attrs, filp); |
| } |
| |
| long vfs_truncate(struct path *path, loff_t length) |
| { |
| struct inode *inode; |
| struct vfsmount *mnt; |
| long error; |
| |
| inode = path->dentry->d_inode; |
| mnt = path->mnt; |
| |
| /* For directories it's -EISDIR, for other non-regulars - -EINVAL */ |
| if (S_ISDIR(inode->i_mode)) |
| return -EISDIR; |
| if (!S_ISREG(inode->i_mode)) |
| return -EINVAL; |
| |
| error = mnt_want_write(path->mnt); |
| if (error) |
| goto out; |
| |
| error = inode_permission2(mnt, inode, MAY_WRITE); |
| if (error) |
| goto mnt_drop_write_and_out; |
| |
| error = -EPERM; |
| if (IS_APPEND(inode)) |
| goto mnt_drop_write_and_out; |
| |
| error = get_write_access(inode); |
| if (error) |
| goto mnt_drop_write_and_out; |
| |
| /* |
| * Make sure that there are no leases. get_write_access() protects |
| * against the truncate racing with a lease-granting setlease(). |
| */ |
| error = break_lease(inode, O_WRONLY); |
| if (error) |
| goto put_write_and_out; |
| |
| error = locks_verify_truncate(inode, NULL, length); |
| if (!error) |
| error = security_path_truncate(path); |
| if (!error) |
| error = do_truncate2(mnt, path->dentry, length, 0, NULL); |
| |
| put_write_and_out: |
| put_write_access(inode); |
| mnt_drop_write_and_out: |
| mnt_drop_write(path->mnt); |
| out: |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(vfs_truncate); |
| |
| static long do_sys_truncate(const char __user *pathname, loff_t length) |
| { |
| unsigned int lookup_flags = LOOKUP_FOLLOW; |
| struct path path; |
| int error; |
| |
| if (length < 0) /* sorry, but loff_t says... */ |
| return -EINVAL; |
| |
| retry: |
| error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
| if (!error) { |
| error = vfs_truncate(&path, length); |
| path_put(&path); |
| } |
| if (retry_estale(error, lookup_flags)) { |
| lookup_flags |= LOOKUP_REVAL; |
| goto retry; |
| } |
| return error; |
| } |
| |
| SYSCALL_DEFINE2(truncate, const char __user *, path, long, length) |
| { |
| return do_sys_truncate(path, length); |
| } |
| |
| #ifdef CONFIG_COMPAT |
| COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length) |
| { |
| return do_sys_truncate(path, length); |
| } |
| #endif |
| |
| static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) |
| { |
| struct inode *inode; |
| struct dentry *dentry; |
| struct vfsmount *mnt; |
| struct fd f; |
| int error; |
| |
| error = -EINVAL; |
| if (length < 0) |
| goto out; |
| error = -EBADF; |
| f = fdget(fd); |
| if (!f.file) |
| goto out; |
| |
| /* explicitly opened as large or we are on 64-bit box */ |
| if (f.file->f_flags & O_LARGEFILE) |
| small = 0; |
| |
| dentry = f.file->f_path.dentry; |
| mnt = f.file->f_path.mnt; |
| inode = dentry->d_inode; |
| error = -EINVAL; |
| if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) |
| goto out_putf; |
| |
| error = -EINVAL; |
| /* Cannot ftruncate over 2^31 bytes without large file support */ |
| if (small && length > MAX_NON_LFS) |
| goto out_putf; |
| |
| error = -EPERM; |
| if (IS_APPEND(inode)) |
| goto out_putf; |
| |
| sb_start_write(inode->i_sb); |
| error = locks_verify_truncate(inode, f.file, length); |
| if (!error) |
| error = security_path_truncate(&f.file->f_path); |
| if (!error) |
| error = do_truncate2(mnt, dentry, length, ATTR_MTIME|ATTR_CTIME, f.file); |
| sb_end_write(inode->i_sb); |
| out_putf: |
| fdput(f); |
| out: |
| return error; |
| } |
| |
| SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length) |
| { |
| return do_sys_ftruncate(fd, length, 1); |
| } |
| |
| #ifdef CONFIG_COMPAT |
| COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length) |
| { |
| return do_sys_ftruncate(fd, length, 1); |
| } |
| #endif |
| |
| /* LFS versions of truncate are only needed on 32 bit machines */ |
| #if BITS_PER_LONG == 32 |
| SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length) |
| { |
| return do_sys_truncate(path, length); |
| } |
| |
| SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length) |
| { |
| return do_sys_ftruncate(fd, length, 0); |
| } |
| #endif /* BITS_PER_LONG == 32 */ |
| |
| |
| int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) |
| { |
| struct inode *inode = file_inode(file); |
| long ret; |
| |
| if (offset < 0 || len <= 0) |
| return -EINVAL; |
| |
| /* Return error if mode is not supported */ |
| if (mode & ~FALLOC_FL_SUPPORTED_MASK) |
| return -EOPNOTSUPP; |
| |
| /* Punch hole and zero range are mutually exclusive */ |
| if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) == |
| (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) |
| return -EOPNOTSUPP; |
| |
| /* Punch hole must have keep size set */ |
| if ((mode & FALLOC_FL_PUNCH_HOLE) && |
| !(mode & FALLOC_FL_KEEP_SIZE)) |
| return -EOPNOTSUPP; |
| |
| /* Collapse range should only be used exclusively. */ |
| if ((mode & FALLOC_FL_COLLAPSE_RANGE) && |
| (mode & ~FALLOC_FL_COLLAPSE_RANGE)) |
| return -EINVAL; |
| |
| /* Insert range should only be used exclusively. */ |
| if ((mode & FALLOC_FL_INSERT_RANGE) && |
| (mode & ~FALLOC_FL_INSERT_RANGE)) |
| return -EINVAL; |
| |
| if (!(file->f_mode & FMODE_WRITE)) |
| return -EBADF; |
| |
| /* |
| * We can only allow pure fallocate on append only files |
| */ |
| if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode)) |
| return -EPERM; |
| |
| if (IS_IMMUTABLE(inode)) |
| return -EPERM; |
| |
| /* |
| * We cannot allow any fallocate operation on an active swapfile |
| */ |
| if (IS_SWAPFILE(inode)) |
| return -ETXTBSY; |
| |
| /* |
| * Revalidate the write permissions, in case security policy has |
| * changed since the files were opened. |
| */ |
| ret = security_file_permission(file, MAY_WRITE); |
| if (ret) |
| return ret; |
| |
| if (S_ISFIFO(inode->i_mode)) |
| return -ESPIPE; |
| |
| /* |
| * Let individual file system decide if it supports preallocation |
| * for directories or not. |
| */ |
| if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
| return -ENODEV; |
| |
| /* Check for wrap through zero too */ |
| if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0)) |
| return -EFBIG; |
| |
| if (!file->f_op->fallocate) |
| return -EOPNOTSUPP; |
| |
| sb_start_write(inode->i_sb); |
| ret = file->f_op->fallocate(file, mode, offset, len); |
| |
| /* |
| * Create inotify and fanotify events. |
| * |
| * To keep the logic simple always create events if fallocate succeeds. |
| * This implies that events are even created if the file size remains |
| * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE. |
| */ |
| if (ret == 0) |
| fsnotify_modify(file); |
| |
| sb_end_write(inode->i_sb); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(vfs_fallocate); |
| |
| SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len) |
| { |
| struct fd f = fdget(fd); |
| int error = -EBADF; |
| |
| if (f.file) { |
| error = vfs_fallocate(f.file, mode, offset, len); |
| fdput(f); |
| } |
| return error; |
| } |
| |
| /* |
| * access() needs to use the real uid/gid, not the effective uid/gid. |
| * We do this by temporarily clearing all FS-related capabilities and |
| * switching the fsuid/fsgid around to the real ones. |
| */ |
| SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode) |
| { |
| const struct cred *old_cred; |
| struct cred *override_cred; |
| struct path path; |
| struct inode *inode; |
| struct vfsmount *mnt; |
| int res; |
| unsigned int lookup_flags = LOOKUP_FOLLOW; |
| |
| if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */ |
| return -EINVAL; |
| |
| override_cred = prepare_creds(); |
| if (!override_cred) |
| return -ENOMEM; |
| |
| override_cred->fsuid = override_cred->uid; |
| override_cred->fsgid = override_cred->gid; |
| |
| if (!issecure(SECURE_NO_SETUID_FIXUP)) { |
| /* Clear the capabilities if we switch to a non-root user */ |
| kuid_t root_uid = make_kuid(override_cred->user_ns, 0); |
| if (!uid_eq(override_cred->uid, root_uid)) |
| cap_clear(override_cred->cap_effective); |
| else |
| override_cred->cap_effective = |
| override_cred->cap_permitted; |
| } |
| |
| old_cred = override_creds(override_cred); |
| retry: |
| res = user_path_at(dfd, filename, lookup_flags, &path); |
| if (res) |
| goto out; |
| |
| inode = d_backing_inode(path.dentry); |
| mnt = path.mnt; |
| |
| if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) { |
| /* |
| * MAY_EXEC on regular files is denied if the fs is mounted |
| * with the "noexec" flag. |
| */ |
| res = -EACCES; |
| if (path_noexec(&path)) |
| goto out_path_release; |
| } |
| |
| res = inode_permission2(mnt, inode, mode | MAY_ACCESS); |
| /* SuS v2 requires we report a read only fs too */ |
| if (res || !(mode & S_IWOTH) || special_file(inode->i_mode)) |
| goto out_path_release; |
| /* |
| * This is a rare case where using __mnt_is_readonly() |
| * is OK without a mnt_want/drop_write() pair. Since |
| * no actual write to the fs is performed here, we do |
| * not need to telegraph to that to anyone. |
| * |
| * By doing this, we accept that this access is |
| * inherently racy and know that the fs may change |
| * state before we even see this result. |
| */ |
| if (__mnt_is_readonly(path.mnt)) |
| res = -EROFS; |
| |
| out_path_release: |
| path_put(&path); |
| if (retry_estale(res, lookup_flags)) { |
| lookup_flags |= LOOKUP_REVAL; |
| goto retry; |
| } |
| out: |
| revert_creds(old_cred); |
| put_cred(override_cred); |
| return res; |
| } |
| |
| SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) |
| { |
| return sys_faccessat(AT_FDCWD, filename, mode); |
| } |
| |
| SYSCALL_DEFINE1(chdir, const char __user *, filename) |
| { |
| struct path path; |
| int error; |
| unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
| retry: |
| error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); |
| if (error) |
| goto out; |
| |
| error = inode_permission2(path.mnt, path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); |
| if (error) |
| goto dput_and_out; |
| |
| set_fs_pwd(current->fs, &path); |
| |
| dput_and_out: |
| path_put(&path); |
| if (retry_estale(error, lookup_flags)) { |
| lookup_flags |= LOOKUP_REVAL; |
| goto retry; |
| } |
| out: |
| return error; |
| } |
| |
| SYSCALL_DEFINE1(fchdir, unsigned int, fd) |
| { |
| struct fd f = fdget_raw(fd); |
| struct inode *inode; |
| struct vfsmount *mnt; |
| int error = -EBADF; |
| |
| error = -EBADF; |
| if (!f.file) |
| goto out; |
| |
| inode = file_inode(f.file); |
| mnt = f.file->f_path.mnt; |
| |
| error = -ENOTDIR; |
| if (!S_ISDIR(inode->i_mode)) |
| goto out_putf; |
| |
| error = inode_permission2(mnt, inode, MAY_EXEC | MAY_CHDIR); |
| if (!error) |
| set_fs_pwd(current->fs, &f.file->f_path); |
| out_putf: |
| fdput(f); |
| out: |
| return error; |
| } |
| |
| SYSCALL_DEFINE1(chroot, const char __user *, filename) |
| { |
| struct path path; |
| int error; |
| unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
| retry: |
| error = user_path_at(AT_FDCWD, filename, lookup_flags, &path); |
| if (error) |
| goto out; |
| |
| error = inode_permission2(path.mnt, path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); |
| if (error) |
| goto dput_and_out; |
| |
| error = -EPERM; |
| if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT)) |
| goto dput_and_out; |
| error = security_path_chroot(&path); |
| if (error) |
| goto dput_and_out; |
| |
| set_fs_root(current->fs, &path); |
| error = 0; |
| dput_and_out: |
| path_put(&path); |
| if (retry_estale(error, lookup_flags)) { |
| lookup_flags |= LOOKUP_REVAL; |
| goto retry; |
| } |
| out: |
| return error; |
| } |
| |
| static int chmod_common(struct path *path, umode_t mode) |
| { |
| struct inode *inode = path->dentry->d_inode; |
| struct inode *delegated_inode = NULL; |
| struct iattr newattrs; |
| int error; |
| |
| error = mnt_want_write(path->mnt); |
| if (error) |
| return error; |
| retry_deleg: |
| mutex_lock(&inode->i_mutex); |
| error = security_path_chmod(path, mode); |
| if (error) |
| goto out_unlock; |
| newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); |
| newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; |
| error = notify_change2(path->mnt, path->dentry, &newattrs, &delegated_inode); |
| out_unlock: |
| mutex_unlock(&inode->i_mutex); |
| if (delegated_inode) { |
| error = break_deleg_wait(&delegated_inode); |
| if (!error) |
| goto retry_deleg; |
| } |
| mnt_drop_write(path->mnt); |
| return error; |
| } |
| |
| SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode) |
| { |
| struct fd f = fdget(fd); |
| int err = -EBADF; |
| |
| if (f.file) { |
| audit_file(f.file); |
| err = chmod_common(&f.file->f_path, mode); |
| fdput(f); |
| } |
| return err; |
| } |
| |
| SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode) |
| { |
| struct path path; |
| int error; |
| unsigned int lookup_flags = LOOKUP_FOLLOW; |
| retry: |
| error = user_path_at(dfd, filename, lookup_flags, &path); |
| if (!error) { |
| error = chmod_common(&path, mode); |
| path_put(&path); |
| if (retry_estale(error, lookup_flags)) { |
| lookup_flags |= LOOKUP_REVAL; |
| goto retry; |
| } |
| } |
| return error; |
| } |
| |
| SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) |
| { |
| return sys_fchmodat(AT_FDCWD, filename, mode); |
| } |
| |
| static int chown_common(struct path *path, uid_t user, gid_t group) |
| { |
| struct inode *inode = path->dentry->d_inode; |
| struct inode *delegated_inode = NULL; |
| int error; |
| struct iattr newattrs; |
| kuid_t uid; |
| kgid_t gid; |
| |
| uid = make_kuid(current_user_ns(), user); |
| gid = make_kgid(current_user_ns(), group); |
| |
| retry_deleg: |
| newattrs.ia_valid = ATTR_CTIME; |
| if (user != (uid_t) -1) { |
| if (!uid_valid(uid)) |
| return -EINVAL; |
| newattrs.ia_valid |= ATTR_UID; |
| newattrs.ia_uid = uid; |
| } |
| if (group != (gid_t) -1) { |
| if (!gid_valid(gid)) |
| return -EINVAL; |
| newattrs.ia_valid |= ATTR_GID; |
| newattrs.ia_gid = gid; |
| } |
| if (!S_ISDIR(inode->i_mode)) |
| newattrs.ia_valid |= |
| ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; |
| mutex_lock(&inode->i_mutex); |
| error = security_path_chown(path, uid, gid); |
| if (!error) |
| error = notify_change2(path->mnt, path->dentry, &newattrs, &delegated_inode); |
| mutex_unlock(&inode->i_mutex); |
| if (delegated_inode) { |
| error = break_deleg_wait(&delegated_inode); |
| if (!error) |
| goto retry_deleg; |
| } |
| return error; |
| } |
| |
| SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user, |
| gid_t, group, int, flag) |
| { |
| struct path path; |
| int error = -EINVAL; |
| int lookup_flags; |
| |
| if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) |
| goto out; |
| |
| lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; |
| if (flag & AT_EMPTY_PATH) |
| lookup_flags |= LOOKUP_EMPTY; |
| retry: |
| error = user_path_at(dfd, filename, lookup_flags, &path); |
| if (error) |
| goto out; |
| error = mnt_want_write(path.mnt); |
| if (error) |
| goto out_release; |
| error = chown_common(&path, user, group); |
| mnt_drop_write(path.mnt); |
| out_release: |
| path_put(&path); |
| if (retry_estale(error, lookup_flags)) { |
| lookup_flags |= LOOKUP_REVAL; |
| goto retry; |
| } |
| out: |
| return error; |
| } |
| |
| SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group) |
| { |
| return sys_fchownat(AT_FDCWD, filename, user, group, 0); |
| } |
| |
| SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group) |
| { |
| return sys_fchownat(AT_FDCWD, filename, user, group, |
| AT_SYMLINK_NOFOLLOW); |
| } |
| |
| SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group) |
| { |
| struct fd f = fdget(fd); |
| int error = -EBADF; |
| |
| if (!f.file) |
| goto out; |
| |
| error = mnt_want_write_file(f.file); |
| if (error) |
| goto out_fput; |
| audit_file(f.file); |
| error = chown_common(&f.file->f_path, user, group); |
| mnt_drop_write_file(f.file); |
| out_fput: |
| fdput(f); |
| out: |
| return error; |
| } |
| |
| int open_check_o_direct(struct file *f) |
| { |
| /* NB: we're sure to have correct a_ops only after f_op->open */ |
| if (f->f_flags & O_DIRECT) { |
| if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) |
| return -EINVAL; |
| } |
| return 0; |
| } |
| |
| static int do_dentry_open(struct file *f, |
| struct inode *inode, |
| int (*open)(struct inode *, struct file *), |
| const struct cred *cred) |
| { |
| static const struct file_operations empty_fops = {}; |
| int error; |
| |
| f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK | |
| FMODE_PREAD | FMODE_PWRITE; |
| |
| path_get(&f->f_path); |
| f->f_inode = inode; |
| f->f_mapping = inode->i_mapping; |
| |
| if (unlikely(f->f_flags & O_PATH)) { |
| f->f_mode = FMODE_PATH; |
| f->f_op = &empty_fops; |
| return 0; |
| } |
| |
| if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) { |
| error = get_write_access(inode); |
| if (unlikely(error)) |
| goto cleanup_file; |
| error = __mnt_want_write(f->f_path.mnt); |
| if (unlikely(error)) { |
| put_write_access(inode); |
| goto cleanup_file; |
| } |
| f->f_mode |= FMODE_WRITER; |
| } |
| |
| /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */ |
| if (S_ISREG(inode->i_mode)) |
| f->f_mode |= FMODE_ATOMIC_POS; |
| |
| f->f_op = fops_get(inode->i_fop); |
| if (unlikely(WARN_ON(!f->f_op))) { |
| error = -ENODEV; |
| goto cleanup_all; |
| } |
| |
| error = security_file_open(f, cred); |
| if (error) |
| goto cleanup_all; |
| |
| error = break_lease(inode, f->f_flags); |
| if (error) |
| goto cleanup_all; |
| |
| if (!open) |
| open = f->f_op->open; |
| if (open) { |
| error = open(inode, f); |
| if (error) |
| goto cleanup_all; |
| } |
| if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) |
| i_readcount_inc(inode); |
| if ((f->f_mode & FMODE_READ) && |
| likely(f->f_op->read || f->f_op->read_iter)) |
| f->f_mode |= FMODE_CAN_READ; |
| if ((f->f_mode & FMODE_WRITE) && |
| likely(f->f_op->write || f->f_op->write_iter)) |
| f->f_mode |= FMODE_CAN_WRITE; |
| |
| f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC); |
| |
| file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping); |
| |
| return 0; |
| |
| cleanup_all: |
| fops_put(f->f_op); |
| if (f->f_mode & FMODE_WRITER) { |
| put_write_access(inode); |
| __mnt_drop_write(f->f_path.mnt); |
| } |
| cleanup_file: |
| path_put(&f->f_path); |
| f->f_path.mnt = NULL; |
| f->f_path.dentry = NULL; |
| f->f_inode = NULL; |
| return error; |
| } |
| |
| /** |
| * finish_open - finish opening a file |
| * @file: file pointer |
| * @dentry: pointer to dentry |
| * @open: open callback |
| * @opened: state of open |
| * |
| * This can be used to finish opening a file passed to i_op->atomic_open(). |
| * |
| * If the open callback is set to NULL, then the standard f_op->open() |
| * filesystem callback is substituted. |
| * |
| * NB: the dentry reference is _not_ consumed. If, for example, the dentry is |
| * the return value of d_splice_alias(), then the caller needs to perform dput() |
| * on it after finish_open(). |
| * |
| * On successful return @file is a fully instantiated open file. After this, if |
| * an error occurs in ->atomic_open(), it needs to clean up with fput(). |
| * |
| * Returns zero on success or -errno if the open failed. |
| */ |
| int finish_open(struct file *file, struct dentry *dentry, |
| int (*open)(struct inode *, struct file *), |
| int *opened) |
| { |
| int error; |
| BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */ |
| |
| file->f_path.dentry = dentry; |
| error = do_dentry_open(file, d_backing_inode(dentry), open, |
| current_cred()); |
| if (!error) |
| *opened |= FILE_OPENED; |
| |
| return error; |
| } |
| EXPORT_SYMBOL(finish_open); |
| |
| /** |
| * finish_no_open - finish ->atomic_open() without opening the file |
| * |
| * @file: file pointer |
| * @dentry: dentry or NULL (as returned from ->lookup()) |
| * |
| * This can be used to set the result of a successful lookup in ->atomic_open(). |
| * |
| * NB: unlike finish_open() this function does consume the dentry reference and |
| * the caller need not dput() it. |
| * |
| * Returns "1" which must be the return value of ->atomic_open() after having |
| * called this function. |
| */ |
| int finish_no_open(struct file *file, struct dentry *dentry) |
| { |
| file->f_path.dentry = dentry; |
| return 1; |
| } |
| EXPORT_SYMBOL(finish_no_open); |
| |
| char *file_path(struct file *filp, char *buf, int buflen) |
| { |
| return d_path(&filp->f_path, buf, buflen); |
| } |
| EXPORT_SYMBOL(file_path); |
| |
| /** |
| * vfs_open - open the file at the given path |
| * @path: path to open |
| * @file: newly allocated file with f_flag initialized |
| * @cred: credentials to use |
| */ |
| int vfs_open(const struct path *path, struct file *file, |
| const struct cred *cred) |
| { |
| struct inode *inode = vfs_select_inode(path->dentry, file->f_flags); |
| |
| if (IS_ERR(inode)) |
| return PTR_ERR(inode); |
| |
| file->f_path = *path; |
| return do_dentry_open(file, inode, NULL, cred); |
| } |
| |
| struct file *dentry_open(const struct path *path, int flags, |
| const struct cred *cred) |
| { |
| int error; |
| struct file *f; |
| |
| validate_creds(cred); |
| |
| /* We must always pass in a valid mount pointer. */ |
| BUG_ON(!path->mnt); |
| |
| f = get_empty_filp(); |
| if (!IS_ERR(f)) { |
| f->f_flags = flags; |
| error = vfs_open(path, f, cred); |
| if (!error) { |
| /* from now on we need fput() to dispose of f */ |
| error = open_check_o_direct(f); |
| if (error) { |
| fput(f); |
| f = ERR_PTR(error); |
| } |
| } else { |
| put_filp(f); |
| f = ERR_PTR(error); |
| } |
| } |
| return f; |
| } |
| EXPORT_SYMBOL(dentry_open); |
| |
| static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op) |
| { |
| int lookup_flags = 0; |
| int acc_mode; |
| |
| /* |
| * Clear out all open flags we don't know about so that we don't report |
| * them in fcntl(F_GETFD) or similar interfaces. |
| */ |
| flags &= VALID_OPEN_FLAGS; |
| |
| if (flags & (O_CREAT | __O_TMPFILE)) |
| op->mode = (mode & S_IALLUGO) | S_IFREG; |
| else |
| op->mode = 0; |
| |
| /* Must never be set by userspace */ |
| flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC; |
| |
| /* |
| * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only |
| * check for O_DSYNC if the need any syncing at all we enforce it's |
| * always set instead of having to deal with possibly weird behaviour |
| * for malicious applications setting only __O_SYNC. |
| */ |
| if (flags & __O_SYNC) |
| flags |= O_DSYNC; |
| |
| if (flags & __O_TMPFILE) { |
| if ((flags & O_TMPFILE_MASK) != O_TMPFILE) |
| return -EINVAL; |
| acc_mode = MAY_OPEN | ACC_MODE(flags); |
| if (!(acc_mode & MAY_WRITE)) |
| return -EINVAL; |
| } else if (flags & O_PATH) { |
| /* |
| * If we have O_PATH in the open flag. Then we |
| * cannot have anything other than the below set of flags |
| */ |
| flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH; |
| acc_mode = 0; |
| } else { |
| acc_mode = MAY_OPEN | ACC_MODE(flags); |
| } |
| |
| op->open_flag = flags; |
| |
| /* O_TRUNC implies we need access checks for write permissions */ |
| if (flags & O_TRUNC) |
| acc_mode |= MAY_WRITE; |
| |
| /* Allow the LSM permission hook to distinguish append |
| access from general write access. */ |
| if (flags & O_APPEND) |
| acc_mode |= MAY_APPEND; |
| |
| op->acc_mode = acc_mode; |
| |
| op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN; |
| |
| if (flags & O_CREAT) { |
| op->intent |= LOOKUP_CREATE; |
| if (flags & O_EXCL) |
| op->intent |= LOOKUP_EXCL; |
| } |
| |
| if (flags & O_DIRECTORY) |
| lookup_flags |= LOOKUP_DIRECTORY; |
| if (!(flags & O_NOFOLLOW)) |
| lookup_flags |= LOOKUP_FOLLOW; |
| op->lookup_flags = lookup_flags; |
| return 0; |
| } |
| |
| /** |
| * file_open_name - open file and return file pointer |
| * |
| * @name: struct filename containing path to open |
| * @flags: open flags as per the open(2) second argument |
| * @mode: mode for the new file if O_CREAT is set, else ignored |
| * |
| * This is the helper to open a file from kernelspace if you really |
| * have to. But in generally you should not do this, so please move |
| * along, nothing to see here.. |
| */ |
| struct file *file_open_name(struct filename *name, int flags, umode_t mode) |
| { |
| struct open_flags op; |
| int err = build_open_flags(flags, mode, &op); |
| return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op); |
| } |
| |
| /** |
| * filp_open - open file and return file pointer |
| * |
| * @filename: path to open |
| * @flags: open flags as per the open(2) second argument |
| * @mode: mode for the new file if O_CREAT is set, else ignored |
| * |
| * This is the helper to open a file from kernelspace if you really |
| * have to. But in generally you should not do this, so please move |
| * along, nothing to see here.. |
| */ |
| struct file *filp_open(const char *filename, int flags, umode_t mode) |
| { |
| struct filename *name = getname_kernel(filename); |
| struct file *file = ERR_CAST(name); |
| |
| if (!IS_ERR(name)) { |
| file = file_open_name(name, flags, mode); |
| putname(name); |
| } |
| return file; |
| } |
| EXPORT_SYMBOL(filp_open); |
| |
| struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt, |
| const char *filename, int flags, umode_t mode) |
| { |
| struct open_flags op; |
| int err = build_open_flags(flags, mode, &op); |
| if (err) |
| return ERR_PTR(err); |
| return do_file_open_root(dentry, mnt, filename, &op); |
| } |
| EXPORT_SYMBOL(file_open_root); |
| |
| long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode) |
| { |
| struct open_flags op; |
| int fd = build_open_flags(flags, mode, &op); |
| struct filename *tmp; |
| |
| if (fd) |
| return fd; |
| |
| tmp = getname(filename); |
| if (IS_ERR(tmp)) |
| return PTR_ERR(tmp); |
| |
| fd = get_unused_fd_flags(flags); |
| if (fd >= 0) { |
| struct file *f = do_filp_open(dfd, tmp, &op); |
| if (IS_ERR(f)) { |
| put_unused_fd(fd); |
| fd = PTR_ERR(f); |
| } else { |
| fsnotify_open(f); |
| fd_install(fd, f); |
| } |
| } |
| putname(tmp); |
| return fd; |
| } |
| |
| SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode) |
| { |
| if (force_o_largefile()) |
| flags |= O_LARGEFILE; |
| |
| return do_sys_open(AT_FDCWD, filename, flags, mode); |
| } |
| |
| SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, |
| umode_t, mode) |
| { |
| if (force_o_largefile()) |
| flags |= O_LARGEFILE; |
| |
| return do_sys_open(dfd, filename, flags, mode); |
| } |
| |
| #ifndef __alpha__ |
| |
| /* |
| * For backward compatibility? Maybe this should be moved |
| * into arch/i386 instead? |
| */ |
| SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode) |
| { |
| return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode); |
| } |
| |
| #endif |
| |
| /* |
| * "id" is the POSIX thread ID. We use the |
| * files pointer for this.. |
| */ |
| int filp_close(struct file *filp, fl_owner_t id) |
| { |
| int retval = 0; |
| |
| if (!file_count(filp)) { |
| printk(KERN_ERR "VFS: Close: file count is 0\n"); |
| return 0; |
| } |
| |
| if (filp->f_op->flush) |
| retval = filp->f_op->flush(filp, id); |
| |
| if (likely(!(filp->f_mode & FMODE_PATH))) { |
| dnotify_flush(filp, id); |
| locks_remove_posix(filp, id); |
| } |
| fput(filp); |
| return retval; |
| } |
| |
| EXPORT_SYMBOL(filp_close); |
| |
| /* |
| * Careful here! We test whether the file pointer is NULL before |
| * releasing the fd. This ensures that one clone task can't release |
| * an fd while another clone is opening it. |
| */ |
| SYSCALL_DEFINE1(close, unsigned int, fd) |
| { |
| int retval = __close_fd(current->files, fd); |
| |
| /* can't restart close syscall because file table entry was cleared */ |
| if (unlikely(retval == -ERESTARTSYS || |
| retval == -ERESTARTNOINTR || |
| retval == -ERESTARTNOHAND || |
| retval == -ERESTART_RESTARTBLOCK)) |
| retval = -EINTR; |
| |
| return retval; |
| } |
| EXPORT_SYMBOL(sys_close); |
| |
| /* |
| * This routine simulates a hangup on the tty, to arrange that users |
| * are given clean terminals at login time. |
| */ |
| SYSCALL_DEFINE0(vhangup) |
| { |
| if (capable(CAP_SYS_TTY_CONFIG)) { |
| tty_vhangup_self(); |
| return 0; |
| } |
| return -EPERM; |
| } |
| |
| /* |
| * Called when an inode is about to be open. |
| * We use this to disallow opening large files on 32bit systems if |
| * the caller didn't specify O_LARGEFILE. On 64bit systems we force |
| * on this flag in sys_open. |
| */ |
| int generic_file_open(struct inode * inode, struct file * filp) |
| { |
| if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) |
| return -EOVERFLOW; |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(generic_file_open); |
| |
| /* |
| * This is used by subsystems that don't want seekable |
| * file descriptors. The function is not supposed to ever fail, the only |
| * reason it returns an 'int' and not 'void' is so that it can be plugged |
| * directly into file_operations structure. |
| */ |
| int nonseekable_open(struct inode *inode, struct file *filp) |
| { |
| filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE); |
| return 0; |
| } |
| |
| EXPORT_SYMBOL(nonseekable_open); |